failed generate html.[err]The following has evaluated to null or missing: ==> solution.tags [in template “1727544124451663874” at line 441, column 152] Tip: If the failing expression is known to be legally null/missing, either specify a default value with myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing

. (These only cover the last step of the expression; to cover the whole expression, use parenthessis: (myOptionVar.foo)!myDefault, (myOptionVar.foo)?? The failing instruction: ==> #list solution.tags?split(” “) as tag [in template “1727544124451663874” at line 441, column 145]